Fixed broken content type headings when class name contains an underscore.

  (No, I don't use underscores in class names, except when doing crazy
   namespacing stuff for multiple FeinCMS base classes sharing the same
   content types...)
ensure_completely_loaded: Only set COMPLETELY_LOADED to True if app cache is ready

Refs #323. Thanks to Simon Meers for the report and for finding a solution.
Merge branch 'master' into next

* master:
  ensure_completely_loaded: Only set COMPLETELY_LOADED to True if app cache is ready
Merge pull request #484 from DrMeers/master

Fixed broken content type headings when class name contains an underscor...
Add an implementation of Array.lastIndexOf to ie_compat.js
Merge branch 'master' into next

* master:
  Add an implementation of Array.lastIndexOf to ie_compat.js
  Fixed broken content type headings when class name contains an underscore.

Conflicts:
	feincms/templates/admin/feincms/item_editor.html
Work on app_reverse and the 1.8 release notes a bit
app_reverse: Massive simplification, only take the urlconf and the language into account by default
Actually do what the pull request says
app_reverse: Actually fall back to any language if current language does not exist

Thanks for noticing, Marc Egli.
Remove an unnecessary assignment

Thanks Simon Bächler for noticing.
Simplify ApplicationContent.closest_match by moving the caching into app_reverse

Also, only cache (urlconf, prefix) instead of the model.
app_reverse cache: Also use settings.SITE_ID if set
Protect the app_reverse cache against offline database changes
Follow the advice of Simon Bächler and do not use new_*
Add a test confirming that invalid moves should not be accepted (model-level validation)

Refs #480.
TreeEditor: Run the save() method of both instances involved in a node move
Remove an obsolete comment
Remove PageAdmin.unknown_fields

Refs #482.
Deprecate the automatic collection of model fields